From the Sacramento Bee : The proponents of the recall of Sen. Jeff Denham announced turning in 50,000 signatures to unseat the Central Valley Republican on Friday ...

The proponents of the recall of Sen. Jeff Denham announced turning in 50,000 signatures to unseat the Central Valley Republican on Friday - a move that is likely to set off a bitter and expensive campaign.

The Bee explains why this move is significant:

Denham's district is one of only a handful in the state that aren't solidly in the camp of either Democrats or Republicans. While Democrats hold a strong majority - 25 of 40 seats - in the Senate, they need 27 votes to pass certain key legislation, such as the budget.